Method of and apparatus for treating stereotype matrices



c. M. BIGSBY 1,931,749

METHOD UP AND APPARATUS FOR TREATING STEREOTYPE MATRICES Oct. 24, 1933.

3 Sheets-Sheet l I Filed Jan. 19, 1932 Oct. 24,-1933. c. M. BIGSBY 1,931,749

METHOD OF AND APPARATUS FOR TREATING STEREOTYPE MATRICES Filed Jan. 19, 1932 5 Sheets-Sheet 2 9. 4 Inventor C..M. BIGSBY 1,931,749

METHOD OF AND APPARATUS FOR TREATING STEREOTYPE MATRICES Oct. 24, 1933.

3 Sheets-Sheet 3 Filed Jan. 19, 1952 Inventor Patented Oct. 24, 1933 unirso STATES PATENTQFHC 1,931,749 N Murnon or AND arrAaA'rUs roa'raEA'r- ING STEREOTYPE MATRICES can M. Bigsby, Comptomcaliffi." I Application January 19, 193.2. Serial'No. 587,531" 12 Claims. (01. s4' 1s I v thereonamat,whichisa specially prepared, slightly damp, sheet of papier mach. The mat receives the impression of the type, thereby forming a fiat matrix, which, after being shaped into cylindrical or semi-cylindrical form, hardened. by drying, and preheated or scorched to prevent chilling the metal, is placed in a casting box and a stereotype plate cast therefrom.

In the past, difficulty has been encountered in the above process for the reason that the matrix sometimes became warped or distorted during the drying process, in which case, of course, the stereotype plate cast therefrom was imperfect. Various methods have been tri d for preventing distortion of the matrix during drying, but to the best of my knowledge, none of them have been entirely satisfactory. Y.

One of the proposed methods involves holding the matrix against a heated drying drum by ex hausting air through apertures in the drum, thus tending to create a vacuum to hold the base of the matrix against the drum. This method is subject to the objection that it is very difficultif not impossible, in practice, to produce a perfect seal between the matrix and the drum sothat air escapes therebetween at certain points, thus reducing the vacuum at that point; As a result there may be no pressure holding the -matrix against the drum in spots, and local warping of the matrix may result. Furthermore, the rush of air past portions of the matrix cools those portions and prevents uniform heating. Partly for this reason it is usually necessary to subsequently scorch the matrix in a'separate machine.

It has also been proposed to dry a matrix by placing it within a cylindrical heated drum and rotating the drum at high speed about its axis, the theory being that the matrix will be held against the surface of the drum by centrifugal force. Al though theoretically very desirable, this process has not been entirely satisfactory in operation for the reason that, due to the light Weight of the matrix, it would have to be revolved at a higher speed than it is practicable to obtain, in order to develop the desired centrifugal force,

low rotational speeds.

drum in a plane perpendicular to its axis;

. In accordance with the present invention, I prov vide a combineddryer, former, and scorcher, that utilizescentrifugal force for holding a matrix against a heating drum, but develops this centrifugal force in. a flexible, laminated, weighted cg blanket positioned .on theinside of the matrix,

this blanket. having considerably greater mass per unitarea than the matrix, whereby the desired centrifugal force can be developed at relatively v Abroad object of the'invention is therefore to provide asimple, quick, and highly eiflcient meth- 0d of drying, forming, .and scorchingmatrices,

and ,a machine for carrying out this'metho'd.

. Other-objects and advantages of the invention will become apparent from 'the following detailed description when read in connectionwith the accompanying drawings, in which:

V Figure l is a side 'levational view of my complete machine; r i 1 1 FigureeZ is, a sectionalelevationalview of the main portion of the machine comprising the drum;

Figure 3- is a sectional elevational View ofthe Figure 4 is a detail view showing the construction of a flexible weighted blanket;

. Figure 5 is a developed view of the inside surface of the enclosingc'ase for the drum; Figure 6 is arear end view of. the upper portion of the machine;

Figure '7 is a plan viewof aportionof a matrix; Figure 8 is a sectional view of aportion. of a matrix taken in the plane VIl IVI1I'in Figr 7; Figure 9 is a sectionaldetail View showing a portion of a perfect matrix corresponding to that ofFigure 8, in a casting box; and

1 a Figure, 10 is a sectional view showing a matrix that has been distorted in drying as it would appear in position againstthe circnlar wall of a casting box;

Figure 11 is a section through the flexible weighted blanket. v

Aspreviously outlined, a papier mach matrix 19.0 for stereotyping is prepared from a sheet of damp, pliant, papiermach by forcingit under great pressure against the type form to be reproduced. After being pressed against the type, the sheet appears as shown in Figures 7 and 8, which disclose a; section of matrixbearing the word fI-Iawk. As shOWn-in Figure 8, th.e faces of the letters-are, indented as shown at 1 below the original surface of the sheet shown at 2, so thatthe surfaces ,1 corresponding to each letter llO of the word are all uniformly spaced from the base 3 of the sheet. In other words, the portions of the sheet delineating the letters are of uniform thickness and all lie between two parallel planes intersecting the surfaces 1 and the surfaces 3 respectively. It follows, that if the matrix disclosed is bent into curved form and placed with its back surface against the rigid wall 4 of a casting box as shown in Figure 9, all portions of the surfaces 1 will be uniformly spaced the thickness of the sheet away from the surface of the casting box, hence all portions of these surfaces will be uniformly spaced from the axis of the mold, and the finished stereotype plate formed by casting from this matrix will be perfect in that the surfaces of all the letters, i. e. the printing surfaces, will lie in a cylindrical surface concentric with respect to the axis of the plate.

Referring now to Figure 10, a matrix which has become distorted during drying is shown in position. against the wall 4' of a casting box. In this instance it will be observed that the portions of the matrix 1 corresponding to the face of the type have become warped so that the type face in a plate cast therefrom, instead of lying in a cylindrical surface concentric with the axis of the plate, will be in part, indented below that surface so that those parts, during the printing process, will not be pressed against the paper with sufficient force to print properly.

It is apparent from a study of Figures '7, 8, 9, and '10, that in order to produce a perfect matrix as shown in Figure 9 all portions of the sheet corresponding to the type face should be maintained within a common cylindrical surface.

This result cannot be obtained by binding the matrix against a convexform during the drying process (as has sometimes been done in the past), for the reason that this merely aligns the surfaces 2 (referring to Figure 8), which printing areas against a smooth, concave cylin-' drical form corresponding substantially in curvature to that of the wall of the casting box. I

produce this result by providing means for uni formly pressing every portion of the damp matrix outwardly against a heated cylindrical drying drum, the pressure being produced by a flexible weighted blanket positioned adjacent to surface 1 of the matrix and forced outwardly thereagainst by centrifugal force developed in the blanket when the entire assembly is rotated.

Referring now to Figures 1 and 2, my machine comprises a frame including a front member 5 and a rear member 6 connected together by a base element '7 and a plurality of longitudinally extending bolts 8. A cylindrical case 9 is secured to brackets 10, 11 and 12, extending from the frame member 6 and a bracket 14 extending from frame member 5. Positioned within the case 9 and mounted upon a shaft 15 is a rotatable drum 16. The'drum proper is constructed of an accurately turned metal tube having a smooth inside surface and being of sufficient thickness to resist any deforming forces resulting from its heating and rotation. The drum 16 is preferably secured by welding or riveting to a pair of ring-shaped end supports 17 which are in turn connected to collars 18 by thin radially extending spokes 63, there being only two oppositely extending spokes 63 at each end. The collars 18 are keyed solidly to the shaft 15 and the latter is rotatably mounted on ball bearings 20 in the end frame members 5 and 6. A sprocket 21 is keyed to the rear end of shaft 15 and connected by a chain 22 to a driving sprocket 23 on an electric motor 24.

Rigidly mounted on shaft 15 between collars 18 are a pair of collars 25, these collars being spaced apart longitudinally along shaft 15 as shown in Figure 2. Each collar 25 has formed integrally therewith two opposite radially projecting arms 26 to which are rigidly attached shafts 27 which are thereby rigidly mounted parallel to shaft 15.

Slidably mounted upon shafts 27 are four tray supporting members 28, 29, 30, and 31. Referring now to Figure 3, which discloses an end view of members 28 and 30, each of these membersis shaped roughly in the outline of a fan having its outer edge shaped to define an arc of a circle.

Mounted upon the circular edge of members28 and 29 is a tray 32 having a cylindrical curved surface, and mounted upon members 30 and 31 is a similar tray 33. Trays 32 and 33 are preferably formed of sheet metal and are attached to their supporting members 28, 2 9, 30, and 31, respectively by welding, riveting, brazing, or! any desired method. Each tray 32 and 33 is provided with guides 34 at its sides which in this instance are formed of angle iron riveted thereto.

Inasmuch as the trays 32 and '33 are secured to the members 28, 29, and 30, respectively which are slidably mounted upon the" tubular frame members 27, either of these trays may be pulled out from within the drum 16 by sliding members 28, and 29, or 30 and 31, as the case may be, along the rods 27 on which they are mounted. To facilitate the operation of pulling out or pushing in the trays, handles 55 are provided which extend forwardly from the frame members 29 and 31 respectively. To limit the extent of outward motion of the trays, stop rods 56 are attached to the rear supporting members 28 and 30 respectively, the forward ends of these rods being adapted to contact with the forward supporting members 26 mounted on shaft 15.

Mounted upon each tray 32 and 33 is a flexible weighted blanket 35. This blanket (referring now to Figure 4) may be made in a variety of forms but preferably comprises a central layer 37 of flexible metal mesh construction such as is used in making handbags, enclosed between two sheets of asbestos fabric, 38 and 39 respectively. The mesh 37 is preferably attached to the inner and outer sheets 38 and 39 by being sewed thereto at intervals with fine brass wire or other heat resistant filamentary material. The outer sheet'39 is preferably made of substantially pure asbestos fabric so that it will be very flexible and will readily conform to the shape of the faces 1 (Figure 9) of a matrix. It is necessary, however, that the blanket 35, as a whole, have some stiffness to prevent it piling up and wrinkling under the tangential forces developed when the drum is started and stopped. This stiffness is obtained by reinforcing the lower asbestos sheet 38 with brass wire interwoven therewith. Each blanket 35 is secured against longitudinal or circumferential motion with respect to its supporting tray by pins 40, which are provided with flat heads-brazed or soldered to the mesh 37 of'the pad, and fitting loosely in radial apertures extending through the tray 32 or 33, as the case may be, and reinforcing blocks 41 welded or brazed to the inside surfaces of the trays.

The pins 40, being free to slide radially in the holes in blocks 41, do not interfere with radial movement of the pad, but do prevent any circumferential or longitudinal movement with respect to the trays.

Portions of the forward ends of the trays 32 and 33 are cut outas shown at 58 in Figure 2 to facilitate the removal of matrices as will be described later.

" I The motor24 for rotating the shaft 15 is preferprefer to heat the drum in my machine electrically and to this end I provide strip heaters 43 on the exterior of the drum 16. These heaters extend longitudinally at spaced intervals about the circumference of the drum and are retained in position by rivets or screws 44 at their ends and by a retaining band 45 passing circumferentially aboutthem approximately at the middle of the drum. It is desirable to accurately regulate the tempera ture of the drum and for this purpose I provide at spaced points on the drum thermostatic elements 46, which operate in conjunction with a thermostatic relay 47 to interrupt the current to the heaters 43 whenever the temperature of the drum exceeds a predetermined value. The heaters are supplied with current through three slip rings 48 mounted on the front end of shaft 15. These slip rings contact with three brushes 49 which supply current from a commercial source. Since my device as described comprises two trays 32 and 33 it may be desired to operate only one tray at'times, in which case it is unnecessary to heat that half of the drum adjacent the unused tray. For this reason, three slip rings 48 and cooperating brushes 49 are provided to apply currentv to the heating elements, each of two of the brushes and slip rings supplying current to half the heating elements and one of these rings and brushes, together with the third ring and brush forming the circuit for supplying current to the remaining heating elements. Since circuits for thermostatically controlling heating elements are old and are well understood and are not a part of my invention, it has been considered unnecessary to disclose the specific circuit connections in the drawings.

When a cylindrical drum is rotated itis found that currents of air are induced from the ends of the drum toward the center, from which point the air is thrown outward by centrifugal force. This rush of cool air from the ends of the drum toward the mid-portion tends to cool the ends to a greater extent than the mid-portion; furthermore, there is a greater eifective heat radiating surface at the ends of the drum than elsewhere so that a matrix treated in such'a drum may be overheated at the center and underheated at the ends. To overcome this defect the drum.16 is enclosed in a stationary cylindrical case 9 asmentioned earlier in the description. Case 9 is provided with ring-shaped end walls 50 which approach the end rings 17 on the rotating cylinder 16 as closely as permissible without danger of con tact and resultant friction therebetween. The cylindrical case 9, in combinationwith the end walls 50 substantially enclose the drum and tend to confine the air about the drum, thus greatly conserving the heat and tending to equalize the temperature of the entire drum. To further equalize the temperature, there is provided within case 9 a cylindrical baflie plate 60, which is supported from case 9 by rivets 61 and in turn supports a plurality of baflie plates 51 which extend outwardly at an angle from the mid portion of the baffle plate 60 as shown in the developed view in Figure 5. The baffles 51 project inwardly from the case 9 toward the heaters 43 on drum 9.

The direction of rotation of the drum with respect to the case 9 is shown by the arrow in Figure 5. When the drum 16 is set in rotation in the direction indicated by the arrow in Figure 5, it tends to carry the air around with it as a result of its motion. This air will be intercepted by baflies 51, which, because of their angle, tend to urge the air contacting them toward the ends of the drum; thus the pressure at the ends of the drum will become greater than the pressure at the center and a return flow of air from the ends to the centerwill result outside of the cylindrical baffle 60. The result is a circulation of air outwardly from the mid-portion of drum l6 to'the ends thereof and thence back along the paths between the baffle 60 and the case 9 and through ports 62 in bafile 60, as indicated by the arrows in Figure 2. This circulation of air from the middle of the drum toward the ends thereof tends to equalize the heat and prevent the middle of the drum becoming hotter than the ends.

The device is operated as follows:

The electric current is first applied to the heating element 43 on drum l6 by'closing a switch in the circuit thereof, which is not shown in the drawings but may be located at any convenient point. "The power is preferably applied to these elements some little time in advance of the drying operation to permit the drum to be heated up to its full temperature. Thereafter the temperature is automatically maintained by the thermostatic control means which includes the temperature sensitive elements 46.

When the drum has been raised to the proper temperature, the matrix to be dried is placed in position between one of the pads 35 and the drum. The actual operation of inserting the matrix into position between the pad and drum is carried out as follows:

The drum is stopped with its diametrically opposite, radially extending supporting spokes 63 in horizontal position so that one of the trays is in its uppermost position and the other in its lowermost'position as shownin Figure 3. The uppermost tray, in this case, tray 32,is then pulled out of the drum by grasping handle 55 and sliding the supporting members 28 and 29 outwardly along the guides 27. This brings the upper tray to the position shown in Figure 1. The operator then curves the matrix to be dried with his hands to conform it approximately to the curvature of the drum and slips it in between the blanket on tray 32 and the drum as far as it will go. The movement of the matrix inwardly on handle 55 inward.

top of the pad 35 is limited by contact with'the studs 65 which protrude upwardly through the rear edge ofthe tray a sufficient distance to just clear the drum 16.

When the drum is stationary thepad 35 on the upper'tray 32 is supported entirely by the tray and clears the inside surface of drum 16 approximately aquarter of an inch. Since the greatest thickness of a matrix (referring to Figure 8) seldom if ever; exceeds an eighth of an inch, ample space is provided between the pad and drum'to insert the matrix.

When the matrix rests on pad 35 on tray 32 and is properly centered thereon, the tray is reinserted completely within the drum by pushing In this latter position the matrix lies completely within the drum 16 and is exposed to the heat radiated therefrom, so that it begins to dry.

In my apparatus it is possible to develop sufficient pressure between the blanket 35 and the drum 16 to actually reduce the depth and con tour sharpness of the impressions in a matrix to an undesirable extent if the drum were rotated while the matrix was in the fresh, pliant condition in which it came from the molding machine. Obviously, this result is to be avoided, and is avoided in practice by heating the matrix in the drum for about thirty seconds before rotating the drum. This preheating hardens the matrix sufficiently to fix the depth and sharpness of the contour to such an extent that it will not subsequently flatten out under the pressure of blanket 35 when the drum is rotated.

After the preheating, the drum is set into rotation and brought up to full speed by closing the switch 42 supplying power to the electric motor 24. The rotation of the drum throws the weighted blanket 35 outward against the face of the matrix and thereby presses the rear surfaces 3 back of the printing areas of the matrix (referring again to Figure 8) solidly against the drum 16 to prevent these portions from warpingas they might do if not positively held in the proper'plane during the final drying process. I have found that by heating the drum to a temperature of 400 degrees and preheating the matrix for thirty seconds with the drum stationary and thereafter leaving it in the rotating drum for one minute. that the matrix is thoroughly dried and hardened, is accurately set to the proper curvature, and is scorched or heated substantially to the temperature of molten type metal sothat after being removed from the drier it can be immediately placed in a casting box and a plate cast'therefrom.

To remove'the matrix from the drier, the drum isstopped by cutting off the power, or, preferably, by first setting the switch to run the motor in the opposite direction. The reverse torque developed in the motor 24.- very quickly brings the drum to a stop. Of course, at the moment when it stops the switch 42 is, thrown into off position to prevent acceleration of the drumin the opposite directionj The tray bearing the matrix is then pulled out by means of handle 55, and the hot matrix removed by grasping its free edge and pullingit outbetween the pad and the drum. The cut-away portions 58 of the forward edges of the trays permit the edges of the pads 35 to be pressed down at these points away from the matrix to permit the operator to grasp the edge of the matrix to remove it. I

The operation of the machine has been de-' scribed where only one matrix is to be treated.

In this instance only that half of the drum 16 juxtaposed to the tray being used need of course be heated. To properly balance the drum during rotation it is desirable to place a fire-proof blank or an old matrix inv the opposite tray to. com.- pensate for the weight of the matrix being treated.

' If two matrices are to be treated simultaneously the process is carried out exactly as described except that after one-matrixhas been inserted. the drum is rotated half a revolutionand theother matrix inserted in the opposite tray; The two matrices are then treated simultaneously by rotating the drum exactly as already described.

I claim: 1. In a machine for treating stereotype matrices, a rotatable-member having a heated cylindrically concave curved face at least approximateradial path. a I

2. A machine as described in claim. 1, in which said flexible element constructed of heat resistant, woven fabric weighted with a layer of flexible metallic material. a i '5 3. A machine for treating matrices as described in claim 1 in which said flexible element comprises,.at least in part, a layer of metal mesh positioned between and sewed to two layers of heat resistant fabric, one of said layers having a stiffening reinforcing therein.

d. In a machine for treating stereotype matrices,'a rotatably mounted shaft, an element having a cylindrical concave surface attached to and positioned symmetrically with respect to saidshaft, a tray secured to said shaft for holding a matrix adjacent to said surface and approximately in the same contour as said surface, and a weighted flexible blanket also supported by said tray and forming a backing for said matrix for forcing all portions of the back surface of said matrix that are juxtaposed to the printing areas thereon uniformly outward'against said surface when said shaft is rotated. a

5. In a machine for treating stereotype matrices, a rotatably mounted shaft, an element having a cylindrical concave surface attached to and positioned symmetrically withv respect to said shaft, a tray to receive thematrix, said tray having substantially the'same curvature as said surface, means for mounting said tray adjacent said surface and fixed against radial and circumferential motion with respect to said element, a flexible blanket mounted on said.- tray and fixed with respect thereto against longitudinal and circumferential, motion but movable radially ,be tween said tray and the inner surface of said element.

6. In a machine for treating stereotype matrices, a rotatably mounted shaft, anelement having a cylindrical, concave surface attached to 'but spaced from said shaft, atray having sub,-

stantially the same curvature'as said surface, and longitudinally slidable means formounting said tray adjacent said surface whereby said tray is slidable longitudinally but fixed radially with respect to said shaft, -a flexible blanketmounted on said tray and fixed with respect thereto 7. In a machine for treating stereotype mat rices, a rotatably mounted shaft, an element having a cylindrical, concave surface attached to but spaced from said shaft, a plurality of trays having substantially the same curvature as said surface and longitudinally slidable means for mounting said trays at circumferentially spaced positions adjacent said surface whereby they are slidable longitudinally but fixed radially with respect to said shaft, a flexible weighted blanket mounted on each tray and fixed with respect thereto against longitudinal and circumferential motion but movable radially between its associated tray and said surface of said element.

8. In a machine for treating stereotype matrices, a rotatably mounted shaft, a cylindrical drum positioned concentrically about said shaft and secured thereto at each end by diametrically opposite radial arms, other arms extending radially from said shaft, longitudinal supporting members secured to said other arms and a tray slidably mounted on said longitudinal supporting members whereby it is movable from a position entirely within said drum to a second position in which it protrudes from the end of said drum, means on said tray for supporting a matrix and means for rotating the drum.

9. In a machine for treating stereotype matrices, a rotatably mounted shaft, a cylindrical drum positioned concentrically about said shaft and secured to said shaft at each end by diametrically opposite, radially extending arms, other arms extending radially from said shaft, longitudinal supporting members secured to said other arms, and a pair of trays slidably mounted on said longitudinal supporting members whereby said trays are slidable from positions entirely within said drum to second positions in which they protrude from the end of said drum between said diametrically opposite radially extending arms.

10. In a machine for treating stereotype matrices, a rotatably mounted shaft, an element havbut spaced from said shaft, a tray having subg stantially the same curvature as said surface, and longitudinal slidable means for mounting said tray adjacent said surface whereby said tray is slidable longitudinally but fixed radially with respect to said shaft, a flexible blanketv mounted on said tray, said tray being provided with a plurality of guide ways extending radially therethrough, and a plurality of guide members, the outer ends of which are secured to said flexible blanket, said guides projecting radially inwardly through the guideways in said tray, said guides restraining said blanket from longitudinal or circumferential motion with respect to said tray but permitting said blanket to move radially between said tray and said surface.

while said drum is rotated, heating elements on said drum,.a stationary case surrounding said drum to prevent loss of heat'therefrom, said case containingspirally directed baflles for circulating air in contact with the outer surface of said drum from the middle of said drum tothe ends thereof.

12. In a machine for treating stereotype matrices a cylindrical drum mounted to rotate about its axis, means within said drum for supporting an object to be heat-treated adjacent said drum while said drum is rotated, heating elements on said drum, a stationary cylindrical case surrounding said drum to prevent loss of heat therefrom, a cylindrical baffle plate surrounding said drum and spaced between said drum and case, and spirally directed bafiies projecting inwardly from said cylindrical baffle plate for circulatingv air in contact with said drum from the middle of said drum towards the ends thereof, said cylindrical baffle plate being provided with apertures at its mid portion to permit passage of air therethrough.

CARL M. BIGSBY. 

